Free-standing vertically aligned tin disulfide nanosheets for ultrasensitive aptasensor design toward Alzheimer?s diagnosis applications

Despite a single drug, Aducanumab, recently approved by the U.S. Food and Drug Administration for Alzheimer's disease (AD)-modifying treatments, the development of non-invasive, highly sensitive, and early screening de-vices to halt the disease remains a critical challenge. In this study, an electrochemical biosensor for amyloid-beta (42) oligomers (A beta Os) detection based on immobilized DNA aptamer onto vertical aligned tin disulfide nano -sheets (SnS2 NSs) is developed for the first time. Highly crystalline, uniform, and vertical aligned SnS2 NSs were synthesized via a facile chemical vapor deposition (CVD) process. The sensing platform, comprising of A beta (42) -specific capture aptamer covalently immobilized onto self-assembled-3-mercaptopropyl-trimethoxysilane (MPTMS)-SnS2 binds specifically toward A beta Os. The biosensor can detect the A beta Os at wide linear concentra-tion range from 10-4 to 103 ng/mL with a low limit of detection (LOD) of 238.9 fg/mL and 56.9 fg/mL in physiological buffer and human serum (HS), respectively. The developed biosensor was successfully used to detect A beta Os in the mice blood serum samples indicating its potential for clinical application in Alzheimer's biomarker detection. Moreover, the SnS2-aptasensor shows good stability, selectivity, and interference -resistance. The predominant edge-plane active site and energetically preference for vertical SnS2 over its planar structure were unveiled by density-functional theory calculations which emphasize the advantages of applying nanomaterial with vertical orientated configuration into electrocatalytic reaction. The as-designed SnS2-aptasensor could shed light not only on multifunctional electrochemical biosensor design, but also for advancements on future Alzheimer's diagnosis.

Automated summary

In this study, an electrochemical biosensor for the detection of amyloid-beta (42) oligomers (A beta Os) in Alzheimer's disease is developed using tin disulfide nano-sheets. The biosensor shows high sensitivity and can detect A beta Os in physiological buffer and human serum. It also exhibits good stability and selectivity. The findings provide new insights for future advancements in Alzheimer's diagnosis.